Help me align h4 headlights with sharp cutoff on lifted rig?

I finally changed out the 7" round sealed beam lights on the tow rig to h4 lights (bulbs and housing)

These lights have a nice sharp cut-off like other modern lights...

What I can't figure out is how to adjust them using the 25 ft wall method.

I found one place on the 'net (and we know the 'net is always right) that you get the cut-off to be 2" lower than the center line height of the bulb @ 25 feet. The same page said if your headlight is 39"+ off the ground that you go by 4" @ 25 feet. The Centerline height of the bulb in the Van is 40"

Since I'm not used to sharp cut-off lights I figured I'd ask.. "How far out 'should' the cutoff be?".

When I set it @ 4" drop at 25 ft (on the wall method) The cut-off is out there a few hundred feet if not more (can't measure that far).. but it looks like I'm going to be blinding people..

If I set it to 2" drop I don't even see the cut-off...

Short of me parking the Van (vehicle with the h4 bulbs) and driving the Honda towards it to see if I blind myself, how can I get these set right?...

I'd appreciate any tips/tricks/info on this...

~Mark

 

[Maniak]

*bump*...

 

[J_Westy]

Since I'm not used to sharp cut-off lights I figured I'd ask.. "How far out 'should' the cutoff be?".

Short of me parking the Van (vehicle with the h4 bulbs) and driving the Honda towards it to see if I blind myself, how can I get these set right?...

I'd appreciate any tips/tricks/info on this...

~Mark

Yeah the 25' rules don't work so well on a lifted truck...

When I did this with our lifted Wrangler, I ended up kind of doing it by trial-and-error. I parked a low car out in front of the Jeep and adjusted the cut off to not be obnoxious, then went to a wall and evened them up left to right.

The great thing about a clean H4 cut-off is that you can be precise and get a good balance between visibility and glare for everybody else. If you're too high, I'm sure other drivers will let you know. I found that with the Hellas I used, I had to aim them kind of low on low-beams anyway to get a good high beam pattern... otherwise I was lighting up the sky on high beams

Good luck

 

[Maniak]

I adjusted the lights and seem to have them close.. (no one tried to run me off the road for having them on this morning).

I set the truck 12 ft from a wall and set the beams to about 2.5" lower than the centerline height.

I then got a feel for the height of my head when I'm in the Honda (kneeling) and kneeled in front and to the side of the Van and adjusted the lights up until they would blind me when simulating the honda height. I then adjusted it back down some...

I drove to work in the dark and they were shooting out far enough. I could use them a little higher but I don't want them to be too high when I put the trailer on the van next week.

I noticed the cut-off is just under the wide mirror of the small car (not short car) that was in front of me at a light today so I'd say I have it as good as I'm going to get, for now..

~Mark

 

[Anime]

The wall method, or the measuring in general, stops working past a certain headlamp height since it's too high relative to other vehicles. The lamps themselves were also designed for passenger cars, so they are slightly less effective the farther they get from the road, and it makes them harder to aim properly for visibility when taking into account the beam relative to other vehicles. This is why you see semi trucks with headlights down near bumper height.

A general way of doing it is just making sure the cutoff is below the rear window of the average passenger car at the minimum following distance - somewhere around 40-50 ft.

The idea of the wall aiming is to show where the cutoff and brightest spots of the beam are, at the 25 ft distance you would probably be stopped at behind another vehicle at a red light or stop sign - so the lamps aren't blinding them the entire time.

There is no way to tweak the formula for lifted vehicles, since where the headlamps need to be aimed is still relative to other (lower) vehicles - the only thing you can do is lower the headlamps. Other than that, it's just trial and error, finding the "sweet spot" between aiming the cutoff to not blind other drivers and having the beam give an even spread of light on the road, with the brightest part in an effective spot.

You can still use the wall method to aim the lamps horizontally, so they're putting the light slighty to the passenger side, then just adjust them vertically by trial and error after that.